Surveillance for parasites in unaccompanied minor refugees migrating to Germany in 2015

In 2015, most of the refugees arriving in Germany originated from countries with poor hygienic and sanitary conditions. Stool samples of 1,230 minor refugees unaccompanied by adults were investigated for possible parasites. Giardia lamblia was by far the most frequently detected parasite (n=165); all other parasites were considerably less frequent and encountered in the following order: Hymenolepis nana (n=23), Entamoeba histolytica (n=17), Trichuris trichiura (n=8), and Blastocystis hominis (n=1). Ascaris lumbricoides was not detected among any of the screened refugees. Considerable differences in prevalence rates in refugees originating from different countries could be observed.


Introduction
The current refugee crisis demands European union-wide surveillance [1]. The Robert Koch-Institute in Germany has informed all physicians about possible epidemiologically relevant infectious diseases in conjunction with refugees, including vaccine-preventable diseases such as hepatitis A, influenza, pertussis, measles, mumps and varicella, respiratory and gastrointestinal diseases such as tuberculosis and norovirus gastroenteritis. However, only a single parasitic disease, scabies, was included in this information [2]. Most of the refugees in Germany are coming from countries with poor sanitation practices or poor hygienic conditions, especially after the break of the political systems due to terrorism and/or civil war in their country of origin. Therefore it might be assumed that these refugees might harbor parasites. This may not only be a problem, which may have implications in refugee camps with poor sanitation, but may affect health conditions of affected individuals as well.

Method
All unaccompanied minor refugees age 16.0 ± 1.2 years and below 18 years arriving in the South of Hesse, a federal state in the south-west of Germany, from January 1 st to November 10 th 2015, had their stool samples tested for Giardia lamblia, Entamoeba histolytica, Ascaris lumbricoides, Trichuris trichiura, Hymenolepis nana, and Blastocystis. The analyses were performed in the Institute for Medical Microbiology, Bioscientia, Ingelheim, Germany,

Discussion
In general, Giardiasis and Amebiasis are frequent in tropical areas with poor sanitation. These diseases are transmitted through contaminated water or food. Amoeba cause acute and chronic intermittent diarrheal diseases. Giardiasis can cause bloody diarrhea, stomach cramping and fever. In severe cases complications such as gastrointestinal perforation and hematogenous abscesses may occur.
Ascaris infection is one of the most common intestinal worm infections. The geographic distributions of Ascaris spp. are worldwide in areas with warm moist climates and are widely overlapping. Therefore it is surprising, that Ascaris lumbricoides could not be detected in any of the investigated samples. The third most common roundworm of humans is common in warmer areas especially in Asia and to a lesser degree in Africa and South America. Hymenolepis nana (dwarf tapeworm) is a cosmopolitan species though occurring most commonly in temperate zones; it is one of the most common cestodes world-wide [3]. None of the refugees tested reported on gastrointestinal symptoms. Most parasites were detected in less than 2% of the refugees. However, more than 10% of the unaccompanied minor refugees exhibited Giardia lamblia in their stool specimen. In agreement with this data, first findings of wastewater monitoring showed increased contamination of Giardia lamblia in wastewater of a school used as emergency accommodation for about 200 refugees in Frankfurt am Main: 4,600,000 spores/100 l compared to 90,000 spores/100 l in samples of the Frankfurt municipal sewage treatment plant [4]. Because parasitic diseases with the exception of Giardiasis are not notifiable in Germany, no comparison to nationwide data can be made. Currently, there is no evidence of an increase of the Giardiasis notifications neither in the federal state of Hesse nor nationwide. Occasionally, employees of the public health office are contacted and asked for advice when individual cases of helminth diseases occur. Reliable data are not available in Germany as there is no mandatory reporting for these conditions. The data may be compared, however, to a small survey of 102 unaccompanied asylum seekers, arriving in Bielefeld, Germany, with about 20% of them being infected with parasites (7.2% Lambliasis, 6.3% Amoebiasis, 7.6% helminthic diseases) [5] and to the survey of 1,203 refugees in California, 2008-2010, with 12.3% of them being infected with parasites [6].
Catchpole and Coulombier [1] proposed surveillance for communicable diseases in refugees due to missing vaccination such as influenza, measles and varicella, as well as infections and outbreaks of scabies, diarrhea and meningococcal disease. This might be achieved by assessing the data of notifiable diseases, if the criteria "refugee" is made reportable as well or by special surveys in defined migration centers (i.e. [7], [8]). Riccardo et al. highlighted the current available data in the EU and their limitations [9]. Additional studies with data of screening asymptomatic persons for multidrug resistant organisms [10], [11], or parasites, as shown by the data presented here, seem to be necessary to assess the burden of these organisms and parasites in refugees. Moreover, wastewater surveillance, which is already established in environmental monitoring of polio virus in various countries (i.e. Italy and Switzerland [12], [13]), might be helpful in surveillance of parasites as well.